Multi-junction controllable unit with bi-directional current path from anode to gate to render said unit bi-directional



Feb. 17, 1 970 G. J. FISCHER MULTI-JUNCTION CONTROLLABLE UNIT WITHsx-nmacnorm.

cmnm PATH mom ANODE TO GATE TO RENDER sun UNIT sx-mmacnomn Filed Dec. 9,1965 6 Sheets-Sheet 1 56' FIG.2. FIG.3. FIG.4. FIGS. FIGS.

Feb. 17, 1970 a. J. FISCHER ,3

MULTIQJUNCTIO CONTROLLABLE UNIT WITH BI-DIRECTIONAL 'OURRENT PATH FROMMODE T0 GATE 1'0 RENDER SAID UNIT Bil-DIRECTIONAL Filed Dec. 9, 1965 6Sheets-Sheet 2 FIG. I4A. FIG. I4B. FIG. |4C

m /ee -/68 F|G.I5A. F|G.|5B. FIG. I5C.

FIG. ISA. FIG. I65. FIG. I6C.

F|G.I7A. FIG. I75. I FIG.I7C.

FIGLIBA. FIG.I8B. FIGJBC.

FIG. IQA. FIG. I95. FIG. IQC.

FIG. 20A. FIG.2OB. FIG. 20C.

Feb. 17, 1970 a. J. FISCHER 3,495,390

MULTI-JUNGTION CONTROLLABLE UNIT WITH BI-DIBECTIONAL CURRENT PATH FROMODE TO GATE To RENDER SAID UNIT BI-DIRECTIONAL Filed Dec. 9, 1965 eSheets-Sheet 4 7 0;? 228 234 220 228 220 P V230 p N 2% 3 7 N 4232 P|LoAo P 5, N 235 N b 240 A 222 D FIG. 33.

FIG. 34.

FIG. 36.

Feb. 17, 1970 a. J. FISCHER 3,495,390

MULTI-JUNCTION CONTROLLABLE UNIT WITH BI-DIRECTIONAL CURRENT PATH FROMANQDE To GATE TO RENDER SAID UNIT Ell-DIRECTIONAL 6 Sheets-Sheet 5 FiledDec. 9, 1965 N P E 0 3 i a a, 3 3 a, w 6 3 3 Z a 3/ 3 0 8 M w m 3 NPN-2/J F J v PN N .fi D0, #6 2 0 3 3L! )V J 6 a x Z a,

7 3 m 2F 0 N 3 8 m FIG. 40.

FIG. 39.

Feb. 17, 1970 G. J. FISCHER 3,

MULTI-JUNQTION CONTROLLABLE UNIT WITH BI-DIRECTIQNAL CURRENT PATH FROMANODE To GATE T0 RENDER sun UNIT Iii-DIRECTIONAL Filed Dec. 9. 1965 376382 LoAo f 370 37% 7 N 378 p an N 389 372; "1 FIG. 4|. 380 V FIG. 42.

FIG. 43.

6 Sheets-Sheet 6 United States Patent 3,496,390 MULTI-JUNCTIONCONTROLLABLE UNIT WITH III-DIRECTIONAL CURRENT PATH FROM ANODE T0 GATET0 RENDER SAID UNIT BI- DIRECTIONAL George J. Fischer, 2030 Lonedell,Arnold, Mo. 63010 Filed Dec. 9, 1965, Ser. No. 512,655 Int. Cl. H03k3/26 U.S. Cl. 307-305 18 Claims ABSTRACT OF THE DISCLOSURE Acontrollable unit which has a p-n junction, an n-p junction, a secondp-n junction, and a terminal itermediate said n-p junction and saidsecond p-n junction has a bi-directional control circuit between thep-type layer of the first p-n junction and the said terminal; and thatbi-directional control circuit is adapted to have an impedance lowenough to enable said controllable unit to conduct current in bothdirections.

This invention relates to improvements in control systems. Moreparticularly, this invention relates to improvements in devices whichcan control electric power.

It is, therefore, an object of the present invention to provide animproved device which can control electric power.

It is important to be able to apply electric power to a load, to controlthe value of that power, and to shut off that power. In recognition ofthat fact, control devices have been developed which could applyelectric power to a load, could control the value of that power, andcould shut off that power However, those control devices have had manycomponents, and hence those control devices have been expensive andbulky. It would be desirable to provide a control device which couldapply electric power to a load, could control the value of that power,and could shut off that power but which would have only a fewcomponents. The present invention provides such a control device; and itis, therefore, an object of the present invention to provide a controldevice which can apply electric power to a load, can control the valueof that power, and can shut off that power and which has only a fewcomponents.

The control device provided by the present invention utilizes one ormore controllable units and one or more control circuits for thosecontrollable units; and each of those controllable units has a p-typelayer, an n-type layer, a p-type layer, and an n-type layer which form ap-n junction, an n-p junction, and a p-n junction. One of the p-typelayers serves as the anode of the controllable unit, the other p-typelayer serves as an intermediate terminal for that unit, and one of then-type layers serves as the cathode of that unit. The control circuit isconnected between the anode and the intermediate terminal, and thatcontrol circuit will determine the amount of power which the controldevice can apply to a load. In the preferred embodiments of the presentinvention, the control circuits can enable the control devices to supplypower to the loads over the full range from zero power to full power,and to do so in smooth, step-less fashion. It is, therefore, an objectof the present invention to provide a control device that includes acontrollable unit with a p-type layer, an n-type layer, a p-type layer,and an n-type layer which form a p-n junction, an n-p junction and a p-njunction, and that also includes a control circuit connected between thetwo ptype layers and that can supply power to a load 3,496,390 PatentedFeb. 17, 1970 over the full range from zero power to full power, and todo so in smooth step-less fashion.

Other and further objects and advantages of the pressent inventionshould become apparent from an examination of the drawing andaccompanying description.

In the drawing and accompanying description several preferredembodiments of the present invention are shown and described but it isto be understood that the drawing and accompanying description are forthe purpose of illustration only and do not limit the invention and thatthe invention will be defined by the appended claims.

In the drawing, FIG. 1 is a diagrammatic showing of one preferredembodiment of control device that is made in accordance with theprinciples and teachings of the present invention, and the controlcircuit of that control device is an adjustable resistor,

FIG. 2 is a diagrammatic showing of an adjustable capacitor which can beused as the control circuit of the control device of FIG. 1.

FIG. 3 is a diagrammatic showing of an adjustable inductor which can beused as the control circuit of the control device of FIG. 1,

FIG. 4 is a diagrammatic showing of a series-connected adjustableresistor and adjustable capacitor which can be used as the controlcircuit of the control device of FIG. 1,

FIG. 5 is a diagrammatic showing of a series-connected adjustableresistor and adjustable inductor which can be used as the controlcircuit of the control device of FIG. 1,

FIG. 6 is a diagrammatic showing of a series-connected adjustablecapacitor and adjustable inductor which can be used as the controlcircuit of the control device of FIG. 1,

FIG. 7 is a diagrammatic showing of a series-connected adjustableresistor, adjustable capacitor and adjustable inductor which can be usedas the control circuit of the control device of FIG. 1,

FIG. 8 is a diagrammatic showing of a series-connected switch andadjustable resistor which can be used as the control circuit of thecontrol device of FIG. 1,

FIG. 9 is a diagrammatic showing of an adjustable resistance bridgewhich can be used as the control circuit of the control device of FIG.1,

FIG. 10 is a diagrammatic showing of an adjustable capacitance bridgewhich can be used as the control circuit of the control device of FIG.1,

FIG. 11 is a diagrammatic showing of an adjustable inductance bridgewhich can be used as the control circuit of the control device of FIG.1,

FIG. 12 is a diagrammatic showing of another preferred embodiment ofcontrol device that is made in accordance with the principles andteachings of the present invention,

FIG. 13 is a diagrammatic showing of a further preferred embodiment ofcontrol device that is made in accordance with the principles andteachings of the present invention,

FIGS. 14A14C are representations of oscillograms obtained with thecontrol device of FIG. 1 when the load was a forty watt incandescentlamp and the ohmic value of the control circuit was one megohm,

FIGS. ISA-15C are representations of oscillograms obtained with thecontrol device of FIG. 1 when the load was a forty watt incandescentlamp and the ohmic value of the control circuit was three hundred andthirty thousand ohms,

FIGS. 16A-16C are representations of oscillograms obtained with thecontrol device of FIG. 1 when the load was a forty watt incandescentlamp and the ohmic value of the control circuit was ten thousand ohms,

FIGS. 17A-17C are representations of .oscillograms 3 obtained with thecontrol device of FIG. 1 when the load was a forty watt incandescentlamp and the ohmic value of the control circuit was five thousand ohms,

FIGS. 18A-l8C are representations of oscillograms obtained with thecontrol device of FIG. 1 when the load was a forty watt incandescentlamp and the ohmic value of the control circuit was one thousand ohms,

FIGS. l9A-19C are representations of oscillograms obtained with thecontrol device of FIG. 1 when the load was a forty watt incandescentlamp and the ohmic value of the control circuit was one hundred andeighty ohms,

FIGS. 20A-20C are representations of oscillograms obtained with thecontrol device of FIG. 1 when the load was a forty watt incandescentlamp and the ohmic value of the control circuit was one hundred ohms,

FIGS. 21A-21C are representations of oscillograms obtained with thecontrol device of FIG. 1 when the load was a forty watt incandescentlamp and the ohmic value of the control circuit was fifty ohms,

FIGS. 22A-22C are representations of oscillograms obtained with thecontrol device of FIG. 1 when the load was a forty watt incandescentlamp and the ohmic value of the control circuit was ten ohms,

FIG. 23 is a diagrammatic showing of a preferred embodiment of controldevice that is made in accordance with the principles and teachings ofthe present invention and that has two controllable units and onecontrol circuit therefore,

FIGS. 24-31 are representations of oscillograms obtained with thecontrol device of FIG. 23 when the load 'was a forty watt incandescentlamp and the ohmic value of the control circuit was six and six-tenths.megohms, five and six-tenths megohms, three and three-tenths megohms,one and eight-tenths megohms, one megohm, five hundred and sixtythousand ohms, one hundred thousand ohms, and ten ohms, respectively.

FIG. 32 is a diagrammatic showing of a preferred embodiment of controldevice that is made in accordance with the principles and teachings ofthe present invention and that has three controllable units connected toform a three-phase bridge,

FIG. 33 is a diagrammatic showing of a control device that is made inaccordance with the principles and teachings of the present inventionand that can be used as a flip-flop circuit,

FIG. 34 is a diagrammatic showing of a further control device that ismade in accordance with the principles and teachings of the presentinvention and that can be used as a flip-flop circuit,

FIG. 35 is a diagrammatic showing of a control device that is made inaccordance with the principles and teachings of the present inventionand that can be used as a DC. flip-flop circuit,

FIG. 36 is a diagrammatic showing of a control device that is made inaccordance with the principles and teachings of the present inventionand that can be used as a speed control for an electric motor,

FIG. 37 is a diagrammatic showing of a control device that is made inaccordance with the principles and teachings of the present inventionand that can be used as a time delay circuit,

FIG. 38 is a diagrammatic showing of a control device that is made inaccordance with the principles and teachings of the present inventionand that can be used as a slow to make control circuit,

FIG. 39 is a diagrammatic showing of a control device that is made inaccordance with the principles and teachings of the present inventionand that can be used as a slow to break control circuit,

FIG. 40 is a diagrammatic showing of a control device that is made inaccordance with the principles and teachings of the present inventionand that can have a signal injected into the control circuit of thecontrollable unit thereof,

FIG. 41 is a diagrammatic showing of a control device that is made inaccordance with the principles and teachings of the present inventionand that has an adjustable bridge and an adjustable resistor in thecontrol circuit of the controllable unit thereof,

FIG. 42 is a diagrammatic showing of a control device that is made inaccordance with the principles and teachings of the present inventionand that has sensing elements and an adjustable resistor in the controlcircuit of the controllable unit thereof, and

FIG. 43 is a diagrammatic showing of a control device that is made inaccordance with the principles and teachings of the present inventionand that has a conditionsensing element in the control circuit of thecontrollable unit thereof.

Referring to FIG. 1 in detail, the numeral 50 generally denotes acontrollable unit which is made in accordance with the principles andteachings of the present invention; and that unit has four layers 52,53, 55 and 54. The layer 52 is a p-type layer, the layer 53 is an n-typelayer, the layer 55 is a p-type layer, and the layer 54 is an n-typelayer. The layer 52 serves as the anode for the unit 50; and the layer54 serves as the cathode for that unit. A terminal 56 is secured to thelayer 55; and that terminal serves as an intermediate terminal for theunit 50. The layers 52, 53, 55 and 54 of the controllable unit 50 willpreferably be made from silicon pellets in which p-type impurities andn-type impurities have been introduced. However, where desired, thelayers 52, 53, 55 and 54, of the unit 50 could be made from pellets ofanother material such as germanium.

A junction 62 connects one side of a load 67 to the anode 52 and to aterminal 58; and the other side of that load is connected to one side ofa suitable source of alternating current by a conductor 64. A conductor66 extends from the cathode 54 to the other side of that source ofalternating current. As a result, the load 67 and the anode-cathodecircuit of the controllable unit 50 are connected in series across thesource of alternating current. The numeral 60 denotes a terminal whichis connected to the intermediate terminal 56; and an adjustable resistor68 is shown connected between the terminals 58 and 60. That adjustableresistor is the control circuit for the controllable unit 50; and itconstitutes a bi-directional path for current flowing from conductor 64via load 67, junction 62, terminal 58, adjustable resistor 68, terminal60, intermediate terminal 56, layer 55, the p-n junction between thelayers 55 and 54, layer 54, and conductor 66, and for current flowingfrom conductor 66 via layer 54, the n-p junction between layers 54 and55, layer 55, intermediate terminal 56, terminal 60, adjustable resistor68, terminal 58, junction 62, load 67, and conductor 64.

If the adjustable resistor 68 has a high ohmic value, in the range ofseveral megohms, the controllable unit 50 will be essentiallynon-conductive when the conductors 64 and 66 are connected to a suitablesource of alternating current. The voltage supplied by that source ofalternating current will divide across the load 67 and the unit 50; andthat voltage also will divide across that load, the adjustable resistor68, the layer 55, the junction between the layers 55 and 54, and thelayer 54. When the conductor 64 is positive relative to the conductor66, the p-n junction between the layers 55 and 54 will be biased in theforward direction, but the voltage drops across the load 67 and theadjustable resistor 68 will be so large that the voltage across the p-njunction will be too small to render that junction conductive. As aresult, that junction and the overall controllable unit 50 will remainsubstantially non-conductive. When the conductor 66 is positive relativeto the conductor 64, the n-p junction between the layers 54 and 55 willbe biased in the reverse direction; and, as a result, that junction andthe overall controllable unit 50 will remain substantiallynonconductive.

If the ohmic value of the adjustable resistor 68 is reduced to onemegohm, the voltage drop across the load 67 will increase and the votageacross the p-n junction between the layers 55 and 54 will increase; andif, during a half cycle of the alternating current in which theconductor 64 is positive relative to the conductor 66, the voltageacross that p-n junction increases sufliciently to cause current to flowthrough that junction, that junction and the overall controllable unit50 will become conductive and will remain conductive throughout the restof that half cycle. During the next half cycle of the alternatingcurrent, the n-p junction between the layers 54 and 55 will be biased inthe reverse direction; and that junction and the overall controllableunit 50 will be nonconductive throughout that half cycle.

Specifically, as shown by the numeral 160 in FIG. 14A, the voltageacross the load 67 will be essentially zero at the start of a half cyclein which the conductor 64 is positive relative to the conductor 66,because the p-n junction between the layers 55 and 54 and the overallcontrollable unit 50 will essentially be non-conductive. However, as thevoltage increases during that half cycle, the p-n junction between thelayers 55 and 54 and the overall controllable unit 50 will becomeconductive; and thereupon, the voltage across the load 67 willimmediately increase to the value indicated by the numeral 162 in FIG.14A. That voltage will increase until the midpoint of that half cycle isreached, as indicated by the numeral 164 in FIG. 14A; and then thatvoltage will decrease to essentially zero at the end of that half cycle,as indicated by the numeral 166 in FIG. 14A. During the next half cycleof the alternating current, the n-p junction between the layers 54 and55 will be biased in the reverse direction, and that junction and theoverall controllable unit 50 will be non-conductive throughout that halfcycle: and hence the voltage across the load 67 will be essentiallyzero, as indicated by the numeral 168 in FIG. 14A. During succeedingcycles of the alternating current, the voltage across the load 67 willhave the waveform denoted by the numerals 160, 162, 164, 166 and 168 inFIG. 14A.

If the ohmic value of the adjustable resistor 68 is reduced to threehundred and thirty thousand ohms, the voltage drop across the load 67and the voltage across the p-n junction between the layers 55 and 54will be larger; and hence that junction and the overall controllableunit 50 will become conductive closer to the start of each half cycle ofthe alternating current in which the conductor 64 is positive relativeto the conductor 66, as shown by FIG. 15A. During those half cycles inwhich the conductor 66 is positive relative to the conductor 64, the n-pjunction between the layers 54 and 55 and the overall unit 50 will benon-conductive, as shown by FIG. 15A.

If the ohmic value of the adjustable resistor 68 is decreased to tenthousand ohms, the p-n junction between the layers 55 and 54 and theoverall controllable unit 50 will be conductive throughout substantiallyall one hundred and eighty degrees of each half cycle of the alternatingcurrent wherein the conductor 64 is positive relative to the conductor66, as shown by FIG. 16A. When the ohmic value of the adjustableresistor 68 is reduced to that extent, the sum of the voltage dropacross the load 67 and of the voltage drop across that adjustableresistor will be small enough to make the voltage across the n-pjunction between the layers 55. and 54 larger than the break-overvoltage of that junction; and, thereupon, that junction and the overallcontrollable unit 50 will conduct current during these half cycles ofthe alternating current wherein the conductor 66 is positive relative tothe conductor 64. The flow of that current will develop a voltage acrossthe load 67 which will increase until the mid-point of that halfcycle isreached and will then decrease to essentially zero at the end of thathalf cycle.

The voltage that is developed across the load 67, during those halfcycles of the alternating current in which the conductor 66 is positiverelative to the conductor 64, will 6 be very small as shown by FIG. 16A;but that voltage can be increased by further decreasing the ohmic valueof the adjustable resistor 68. Thus as shown by FIGS. 17A22A the voltageacross the load 67, during those half cycles of the alternating currentin which the conductor 66 is positive relative to the conductor 64, canbe in creased by successively reducing the ohmic value of the adjustableresistor 68 to five thousand ohms, one thousand ohms, one hundred andeighty ohms, one hundred ohms, fifty ohms, and ten ohms. When the ohmicvalue of the adjustable resistor 68 is reduced to ten ohms, the voltageacross the load '67, during those half cycles of the alternating currentin which the conductor 66 is positive relative to the conductor 64, willbe substantially as large as the voltage across that load during thosehalf cycles of the alternating current wherein the conductor 64 ispositive relative to the conductor 66. This means that the controldevice of FIG. 1 can be made to supply substantially full power to theload 67 by reducing the ohmic value of the control circuit of thecontrollable unit 50 of that control device.

If desired, the ohmic value of the adjustable resistor 68 can beincreased above one megohm; and, where that is done, the voltage acrossthe load 67 will be essentially zero for longer periods of time duringthose half cycles of the alternating current wherein the conductor 64 ispositive relative to the conductor 66. In fact, the ohmic value of theadjustable resistor 68 can be increased to the point where only a verysmall voltage is developed across the load 67 during those half cyclesof the alternating current wherein the conductor 64 is positive relativeto the conductor 66; and, of course, the voltage across that load willbe essentially zero during those half cycles of the alternating currentin which the conductor 66 is positive relative to the conductor 64. Itshould thus be apparent that the control device of FIG. 1 makes itpossible to vary the voltage and power supplied to the load 67 fromessentially zero to essentially full value. While FIGS. 14A-22Arepresent nine different finite values of voltage that were developedacross the load 67 by the control device of FIG. 1, an infinite numberof different values of voltage can be developed across that load by thatcontrol device. Further, that control device can vary the voltage andpower which it supplies to the load 67 in smooth, step-less fashion.

The control circuit for the controllable unit 50 of FIG. 1 can havedifferent kinds and values of impedance therein. For example, athermistor could be used in place of the adjustable resistor 68 of FIG.1; and that thermistor could be of the type which experiences a decreasein resistance as the temperature thereof increases or could be of thetype which experiences an increase in resistance as the temperaturethereof increases. With a thermistor of the type that experiences adecrease in resistance as the temperature thereof increases, thecontrollable unit 50 will become conductive as the temperature in thearea in which the thermistor is located increases. Subsequently, thatunit will become non-conductive as the temperature in that areadecreases. With thermistors that experience an increase in resistance asthe temperature thereof increases, the controllable unit 50 will becomeconductive as the temperature in the area in which the thermistor islocated decreases. Subsequently, that unit will become non-conductive asthe temperature in that area increases.

Also, heat-sensitive paints or coatings could be substituted for theadjustable resistor 68 of FIG. 1. The ohmic values of the resistances ofthose paints or coatings should, close to one end of the anticipatedtemperature range, be large enough to keep the controllable unit 50non-conductive and should, close to the other end of that temperaturerange, be small enough to render that controllable unit conductive.Moreover, a tapped impedance and a thermostat or contact-equippedthermometer could be substituted for the adjustable resistor 68. Wherethat was done, the overall ohmic resistance of that tapped impedanceshould be great enough to keep the controllable unit 50 non-conductive,but the thermostat or the contact-equipped thermometer should shortenough of that impedance to permit the controllable unit 50 to becomeconductive.

Light-sensitive elements of the photo-resistive type could besubstituted for the adjustable resistor 68; and, as those elementsresponded to the light falling thereon to decrease the resistancethereof, enough current would flow through those light-sensitiveelements to render the controllable unit 50 conductive. When thoselight-sensitive elements subsequently experienced an increase inresistance, as the amount of light falling thereon decreased, thoselight-sensitive elements would render the controllable unit 50non-conductive.

Further, if desired, a pressure-sensitive paint or coating, or apressurestat associated with a tapped impedance, could be substitutedfor the adjustable resistor 68 of FIG. 1. The pressure-sensitive paintor coating could respond to the application of pressure to reduce theohmic value of the control circuit between the junction 62 and theintermediate terminal 56 to the point where the controllable unit 50became conductive. Subsequently, that pressure-sensitive point orcoating could respond to the removal of that pressure to increase itsohmic resistance to the point where that controllable unit again becamenon-conductive. Where the adjustable resistor 68 of FIG. 1 was replacedby a pressurestat and an associated tapped impedance, the pressurestatcould respond to a given change in pressure to short a sufficientportion of the tapped impedance to reduce the impedance of the controlcircuit between the junction 62 and the intermediate terminal 56sufficiently to render the controllable unit 50 conductive.Subsequently, that pressurestat and tapped impedance could respond tothe restoration of the pressure to its initial value to render thecontrollable unit 50 non-conductive again.

Additional, the adjustable resistor 68 of FIG. 1 could be replaced by ahumidistat and a tapped impedance. Changes in humidity could cause thathumidistat to short portions of that impedance and thereby render thecontrollable unit 50 conductive. Subsequent restoration of the humidityto its original level would cause the controllable unit 50 to againbecome non-conductive. Similarly, a combination of a pH meter and atapped impedance could respond to a pre-determined change in the pH of asolution to selectively render the controllable unit 50 conductive.Also, the combination of a microphone and a tapped impedance could bemade to respond to a pre-determined noise level to selectively renderthe controllable unit 50 conductive. Further a microphone and afrequency-sensitive circuit including a variable impedance could be madeto selectively respond to a predetermined frequency to render thecontrollable unit 50 conductive. Similarly, a combination of a variableimpedance and a sensor of any sort of radiation, whether that radiationincludes X-rays, gamma rays, beta particles, neutrons, electrons, ultraviolet light, infra-red rays, could be substituted for the adjustableresistor 68. Actually, any component or combination of components whichcould respond to a pre-determined change of any kind to vary theeffective value of the impedance between the junction 62 and theintermediate terminal 56 could be used to control the conductivity ofthe controllable unit 50.

FIG. 2 shows an adjustable capacitor 70 which can be substituted for theadjustable resistor 68 of FIG. 1. That adjustable capacitor should havea sufiicient range of capacitance to enable it to have an impedancewhich is great enough to keep the controllable unit 50 from becomingconductive and to have an impedance which is small enough to enable thatcontrollable unit to become conductive.

FIG. 3 shows an adjustable inductor 72 which can be substituted for theadjustable resistor 68 of FIG. 1. That adjustable inductor should have asutficient range of inductance to enable it to have an impedance whichis great enough to keep the controllable unit 50 from becomingconductive and to have an impedance which is small enough to enable thatcontrollable unit to become conductive.

As indicated by FIGS. 4-7, the control circuit between junction 62 andthe intermediate terminal 56 of the controllable unit 50 need not besolely resistive, capacitive, or inductive in nature. Instead, thatcontrol circuit can be a composite of an adjustable resistor 68 and anadjustable capacitor 70, as shown by FIG. 4, can be a composite of anadjustable resistor 68 and an adjustable inductor 72, as shown by FIG.5, can be a composite of an adjustable capacitor and an adjustableinductor 72, as shown by FIG. 6, or can be a composite of an adjustableresistor 68 and an adjustable capacitor 70 and an adjustable inductor72, as shown by FIG. 7. Where desired, any of the adjustable resistors68, adjustable capacitors 70 and adjustable inductors 70 in FIGS. 4-7could be replaced by a fixed-value resistor, capacitor or inductor.

Where desired, the control circuit for the controllable unit 50 of FIG.1 can be replaced by a switch 69 and an adjustable resistor 68, as shownby FIG. 8. The setting of that adjustable resistor will be selected sothe ohmic value of the control circuit, constituted by that adjustableresistor and the switch 69, will be small enough to render thecontrollable unit 50 of FIG. 1 conductive whenever the switch 69 isclosed. That controllable unit will, of course, become non-conductivewhenever the switch 69 is re-opened. Appropriate adjustment of thesetting of the adjustable resistor 68 will enable the control circuit ofFIG. 8 to cause the controllable unit 50 of FIG. 1 to supply the desiredvalue of voltage and power to the load 67. The provision of the switch69 enables the adjustable resistor 68 of FIG. 8 to have a much smallerrange than the adjustable resistor 68 of FIG. 1; because the formeradjustable resistor does not have to have sufiicient resistance torender the controllable unit 50 non-conductive.

Where desired, the adjustable resistor 68 of FIG. 8 could be replaced byan adjustable capacitor or an adjustable inductor or a combination ofadjustable impedances. .Also, if desired, the adjustable resistor 68 ofFIG. 8 could be replaced by a fixed resistor, a fixed capacitor, a fixedinductor, or a combination of fixed impedances. Where a fixed resistor,a fixed capacitor, a fixed inductor, or a combination of fixedimpedances was used, the impedance of that resistor, capacitor,inductor, or combina tion of impedances would be small enough to enablethe controllable unit 50 to become conductive whenever the switch 69 wasclosed.

If desired, the control circuit of FIG. 1 could be replaced by aresistance bridge 77, as shown by FIG. 9. That resistance bridgeincludes an adjustable resistor 68 and three other resistors. Ifdesired, one or more of those other three resistors could be madeadjustable. The values of the various resistors of the resistance bridge77 of FIG. 9 should be such that appropriate adjustment of the settingof the adjustable resistor 68 of that bridge could selectively cause thecontrollable unit 50 to become conductive or non-conductive.

A capacitive bridge 79, shown in FIG. 10, or an inductive bridge 81,shown in FIG. 11, also could be substituted for the control circuit ofthe control device of FIG. 1. The capacitive bridge 79 includes anadjustable capacitor 70 plus three other capacitors; and, if desired,one or more of those other three capacitors could be made adjustable.The inductive bridge -81 includes an adjustable inductor 72 plus threeother inductors; and, if desired, one or more of those other threeinductors could be made adjustable. The values of the various capacitorsin the capacitive bridge 79 and the values of the various inductors inthe inductive bridge 71 should be such that appropriate adjustment ofthe adjustable capacitor or inductor could selectively cause thecontrollable unit 50 of FIG. 1 to become conductive or non-conductive.

The controllable unit 50 of FIG. 1 can be fabricated in different sizesto enable it to have different ratings. Also, that controllable unit canbe fabricated in different ways. Preferably, that controllable unit willbe fabricated in the manner in which the four-layered pellets used insilicon controlled rectifiers are fabricated; because the technology ofthe fabrication of such pellets is under stood by several manufacturers.In fact, one of the said four-layered pellets can be used as thecontrollable unit 50 of FIG. 1.

Where desired, a controllable unit 73 can be fabricated from a diode 74,a breakdown diode 76, a breakdown diode 78, and an intermediate terminal80, as shown by FIG. 12. A junction 86 connects the anode of the diode74 to a load 75, and the cathode of that diode is connected directly tothe cathode of the breakdown diode 76. The intermediate terminal 80 isconnected directly to the anodes of the breakdown diodes 76 and 78; andthe cathode of the breakdown diode 78 is connected to a connector 90.That conductor is connected to one side of a suitable source ofalternating current; and a conductor 88 connects the other side of thatsource to the load 75. The control circuit for the controllable unit 73is connected between the junction 86 and the intermediate terminal 80;and that control circuit is a single pole, single throw switch 92.

That switch can be opened to provide a virtually infinite impedancebetween the junction 86 and the intermediate terminal 80; and such animpedance will keep the control device of FIG. 12 non-conductive.Closing of the switch 92 will establish a virtually zero impedancebetween the junction 86 and the intermediate terminal 80; and such animpedance will render the control device of FIG. 12 highly conductive.The values of the current flowing through the breakdown diode 78 will begreater than the values of the current flowing through the junctionbetween the layers 55 and 54 in FIG. 1, because the switch 92 will shortthe series-connected diode 74 and breakdown diode 76; but properselection of the breakdown diode 78 will enable that breakdown diode tocarry those values of current without injury. Because the size andcapacity of the breakdown diode 78 can be greater than the sizes andcapacities of diode 74 and of breakdown diode 76, the controllable unit73 of FIG. 12 can be more rugged than the controllable unit 50 ofFIG. 1. However, the use of three diodes to constitute the controllableunit 73 of FIG. 1'2 makes the overall size and cost of that controllableunit very much larger than the size and cost of the controllable unit 50of FIG. 1.

While a single pole, single throw switch 92 has been shown as thecontrol circuit for the controllable unit 73 of the control device ofFIG. 12, any of the control circuits of FIGS. 1-11 could be substitutedfor that switch. In fact, any component or combination of componentswhich can respond to a predetermined change to sufficiently vary theimpedance of the path from junction 86 to the intermediate terminal 80could be substituted for the switch 92.

FIG. 13 shows a controllable unit 96 which has the rugged and sturdycharacteristics of the controllable unit 73 of FIG. 12 but which has thecompactness of the controllable unit 50 of FIG. 1. The controllable unit96 has a p-type layer 98 and an adjacent n-type layer which can beidentical to the p-type layer 52 and the n-type layer 53 of thecontrollable unit 50 of FIG. 1. The controllable unit 96 has an n-typelayer 100 and an adjacent p-type layer which are considerably larger inarea than the n-type layer 54 and the p-type layer 55 of thecontrollable unit 50 of FIG. 1. The layer 98 serves as the anode and thelayer 100 serves as the cathode. The larger areas of the n-type layer100 and of the adjacent p-type layer of the controllable unit 96 enablethatcontrollable unit to safely pass the large values of current whichwill flow through the junction between those layers when the pathbetween junction 108 and the intermediate terminal 102 of thatcontrollable unit is shorted.

In FIG. 13, a conductor 109 connects one side of a load 110 to one sideof a suitable source of alternating current, and the other side of thatload is connected to the junction 108. The other side of the source ofalternating current is connected to the layer 100. Normally-open relaycontacts 114 serve as the control circuit which is connected between thejunction 108 and the intermediate terminal 102 by terminals 104 and 106.A relay coil 116 is provided to actuate the relay contacts 114. As longas the relay contacts 114 are open, the controllable unit 96 will remainnon-conductive; but when those relay contacts are closed, thatcontrollable unit will become highly conductive. While the relaycontacts 114 are shown as the control circuit for the controllable unit96 in FIG. 13, any of the control circuits of FIGS. 1-12 could besubstituted for those relay contacts. In fact, any component orcombination of components which can respond to a predetermined change tosufficiently vary the impedance of the path from junction 108 to theintermediate terminal 102 could be substituted for the relay contacts114.

As pointed out hereinbefore, and as shown by FIGS. 14A-22A, the controldevice of FIG. 1 can provide voltage wave forms across the load 67 whichvary when the ohmic value of the adjustable resistor 68 is changed.Similar wave forms can be provided across that load by progressivelyvarying the effective impedance of any control circuit that issubstituted for the adjustable resistor 68. As a result, the controldevice of FIG. 1 can provide voltage wave forms across the load 60 whichvary from essentially zero to the full Wave sinusoid of FIG. 22A.

The control device of FIG. 1 also provides other voltage wave forms, asshown particularly by FIGS. 14B and 14C, 158 and 15C, 163 and 16C, 17Band 17C, 183 and 18C, 19B and 19C, 20B and 20C, 21B and 21C, and 22B and22C. The wave forms shown by FIGS. 14B-22B were developed between thejunction 62 and the conductor 66, and thus were developed across theanode-cathode circuit of the controllable unit 50. Those wave forms showthat the average impedance of that controllable unit progressivelydecreases as the impedance of the control circuit for that controllableunit is decreased. The wave forms shown by FIGS. 14C-22C were takenbetween the intermediate terminal 56 and the conductor 66, and thus weretaken across the junction between the layers 55 and 54. The wave formsshown in FIGS. 16C and 17C are essentially square waves; and hence thecontrol device provided by the present invention can serve as a squarewave generator whenever it has an appropriate impedance connectedbetween the anode and the intermediate terminal of the controllable unitthereof.

FIGS. 19C and 20C show voltage wave forms that are generally V-shaped.Consequently, it should be apparent that the control device provided bythe present invention can provide generally V-shaped wave forms wheneveran appropriate impedance is connected between the anode and theintermediate terminal of the controllable unit thereof.

Referring to FIG. 23, the numeral 118 generally denotes a controllableunit which can be identical to the controllable unit 50 of FIG. 1. Thenumeral 126 denotes a second controllable unit that also can beidentical to the controllable unit 50 of FIG. 1. The controllable unit118 has a p-type layer 120 which constitutes the anode of that unit; andthat anode is connected to one side of a suitable source of alternatingcurrent by a junction 138, a load 139, and a conductor 134. The otherside of that source of alternating current is connected to the layer122, which serves as the cathode of the controllable unit 118, by aconductor 136 and a junction 140. The controllable unit 126 has a p-typelayer 128 that serves as the anode of that controllable unit; and thatlayer is connected to the conductor 136 by the junction 140. Thecontrollable unit 126 has an n-type layer 130 which serves as thecathode of that unit, and that layer is connected to the conductor 134by junction 138 and load 139. The intermediate terminal 124 of thecontrollable unit 118 is connected to the intermediate terminal 132 ofthe controllable unit 126 by terminal 144, an adjustable resistor 146,and the terminal 142. The adjustable resistor 146 serves as the controlcircuit for both of the controllable units 118 and 126.

If the ohmic value of the adjustable resistor 146 is great enough,usually in the order of many megohms, insufficient current can flow fromconductor 134 via load 139, junction 138, layer 130 of the controllableunit 126, the junction between that layer and the adjacent p-type layer,the said p-type layer, intermediate terminal 132, terminal 142,adjustable resistor 146, terminal 144, intermediate terminal 124, thelower p-type layer of the controllable unit 118, the junction betweenthat p-type layer and the n-type layer 122, the layer 122, and thejunction 140 to the conductor 136 to render the controllable unit 118conductive. Similarly, the ohmic value of that adjustable resistor canbe great enough so insufficient current can flow from conductor 136 viajunction 140, the n-type layer 122 of the controllable unit 118, thejunction between that layer and the adjacent p-type layer, the saidp-layer, the intermediate terminal 124, terminal 144, adjustableresistor 146, terminal 142, intermediate terminal 132, the upper p-typelayer of the controlable unit 126, the junction between that layer andthe n-type layer 130, junction 138, and load 139 to the conductor 134 torender the controllable unit 126 conductive. However, whenever the valueof the adjustable resistor 146 is reduced sufiiciently and the conductor134 is positive relative to the conductor 136, enough current will flowthrough the layer 130 and the adjacent p-type layer of the controllableunit 126 and through the lower p-type layer and the n-type layer 122 ofthe controllable unit 118 to render the latter controllable unitconductive throughout part of each cycle of the alternating current.Also, whenever the value of the adjustable resistor 146 is reducedsufliciently and the conductor 136 is positive relative to the conductor134, enough current will flow through the n-type layer 122 and theadjacent p-type layer of the controllable unit 118 and through the upperp-type layer and the n-type layer 130 of the controllable unit 126 tothe conductor 134 to render the latter controllable unit conductiveduring another part of each cycle of the alternating current. Thecontrollable unit 118 will be rendered conductive during part of eachpositive-going half cycle of the alternating current, whereas thecontrollable unit 126 will be rendered conductive during part of eachnegative-going half cycle of the alternating current. Thus, thecontrollable unit 126 will be conductive during the portions of thenegative-going half cycle denoted by the numerals 172 and 176 in FIG.24, whereas the controllable unit 118 will be conductive during theportion of the positive-going half cycle denoted by the numeral 174.

The waveform of FIG. 24 was produced when the load 139 was a forty wattincandescent lamp and the ohmic value of the adjustable resistor 146 wassix and sixtenths megohms. By decreasing the ohmic value of theadjustable resistor 146 to five and six-tenths megohms, the on times ofthe controllable units 118 and 126 can be increased, as shown by FIG.25. Further, by progressively decreasing the ohmic value of theadjustable resistor 146 to three and three-tenths megohms, one andoneeighth megohms, one megohm, five hundred and sixty thousand ohms, onehundred thousand ohms, and ten ohms, the on times of the controllableunits 118 and 126 can be increased, as shown by FIGS. 2631. As the ohmicvalue of adjustable resistor 146 is made smaller and smaller, the ontimes of the controllable units 118 and 126 become longer andlonger-approaching full cycle conduction. This means that the voltagedeveloped across the load 139 can be very close to the voltage acrossthe alternating current source, and substantially full power can bedelivered to that load.

While the adjustable resistor 146 has been shown as the control circuitfor the controllable units 118 and 126 of FIG. 23, any of the controlcircuits shown by FIGS. 2-13 can be substituted for that adjustableresistor. Furthermore, any component or combination of components whichcan respond to a predetermined change to vary the impedance thereofsufiiciently to selectively render the controllable units 118 and 126conductive and nonconductive can be used as the control circuit forthose controllable units.

The initial cost of the control device of FIG. 23 can be greater thanthe initial cost of the control device of FIG. 1; because the formercontrol device requires two controllable units whereas the lattercontrol device requires just one controllable unit. However, the controldevice of FIG. 23 is very desirable in that the value of the currentflowing through the n-type layer 130 and the adjacent p-type layer ofcontrollable unit 126, the adjustable resistor 146, and the lower p-typelayer and the layer 122 of the controllable unit 118, and the value ofthe current flowing through the n-type layer 122 and the adjacent p-typelayer of controllable unit 118, the adjustable resistor 146, and theupper p-type layer and the layer 130 of the controllable unit 126 can befar smaller than the value of the current flowing through the layers 55and 54 and the adjustable resistor 68 of FIG. 1. For example, where theohmic values of the adjustable resistor 146 of FIG. 23 and of theadjustable resistor 68 of FIG. 1 were ten ohms, the value of the currentflowing through the former resistor was between one five hundredth andone thousandth of the value of the current flowing through the latteradjustable resistor. As a result, far less energy will be dissipated inthe form of heat in the adjustable resistor 146 than will be dissipatedin the adjustable resistor 68. Also, far less energy will be dissipatedin the form of heat in the junctions adjacent the n-type layers 122 and130, respectively, of the controllable units 118 and 126.

The control device of FIG. 23 is additionally desirable because each ofthe controllable units 118 and 126 thereof is nonconductive for at leasthalf of the time, and thus can cool down. In addition, that controldevice does not require the control circuit thereof to be capable ofwithstanding the very substantial voltages to which the control circuitof the control device of FIG. 1 is subjected. The overall result is thatthe impedance used in the control device of FIG. 23 can be smaller, canhave a lower wattage rating, and will generate less heat than will theimpedance usage in the control device of FIG. 1.

The control devices of FIGS. 1, 12 and 13 are very useful in controllingthe voltage and power which a source of single phase alternating currentcan apply to a load; but it is frequently important to control thevoltage and power which a source of polyphase alternating current canapply to a load. The control device shown by FIG. 32 can easily controlthe voltage and power which a source of three phase alternating currentapplies to a load. In FIG. 32, conductors 180, 182 and 184 areconnectable to a suitable source of three phase alternating current; andthe conductor is connected to the anode of a controllable unit 186 by ajunction 198, the conductor 182 is connected to the anode of acontrollable unit 188 by a junction 200, and the conductor 184 isconnected to the anode of a controllable unit 190' by a junction 202.The controllable units 186, 188 and 190- can be identical to thecontrollable unit 50 of FIG. 1. The cathode of the controllable unit 186is connected to the outer terminal of a phase 192 of a three phase load,the cathode of the controllable unit 188 is connected to the outerterminal of a phase 194 of that load, and the cathode of thecontrollable unit 190 is connected to the outer terminal of a phase 196of that load. The inner terminals of those phases of that load areconnected together. An adjustable resistor 204 is connected between thejunction 198 and the intermediate terminal of the controllable unit 186,an adjustable resistor 206 is connected between the junction 200 and theintermediate terminal of the controllable unit 188, and an adjustableresistor 208 is connected between the junction 202 and the intermediateterminal of the controllable unit 190. The adjustable resistors 204, 206and 208 will preferably have the adjustable portions thereof ganged topermit simultaneous adjustment of the ohmic values of those adjustableresistors. Those adjustable resistors should be selected so the ohmicvalues thereof can be made small enough to render the controllable units186, 188 and 190 conductive.

When the conductors 180, 182 and 184 are connected to a suitable sourceof three phase alternating current, and when the ohmic values of theadjustable resistors 204, 206 and 208 are reduced to levels at which thecontrollable units 186, 188 and 190 can become conductive, thosecontrollable units will successively become conductive and willsuccessively supply power to the various phases 192, 194 and 196 of theload. The amount of power which will be supplied to the various phasesof the load can be controlled by adjusting the settings of theadjustable resistors 204, 206 and 208.

The arrangement shown by FIG. 32 is very useful in controlling theamount of voltage and power which a source of three phase alternatingcurrent can apply to a load. However, that arrangement is merelyrepresenta tive; and other arrangements, which use the controllableunits of the present invention, can be used to control the amount ofvoltage and power which a source of three phase alternating current canapply to a load. Further, other arrangements, which use the controllableunits of the present invention, can be used to control the amount ofvoltage and power which sources of two phase and multi-phase alternatingcurrent can apply to a load.

Referring to FIG. 33, the numerals 220 and 222 denote conductors thatcan be connected to a suitable source of alternating current. Avoltage-dropping resistor 224 has one side thereof connected to theconductor 220; and the other side of that resistor is connected to theanode of a controllable unit 230 by a junction 228 and to the anode of acontrollable unit 232 by junction 228 and a junction 234. Thecontrollable units 230 and 232 can be identical to the controllable unit50 of FIG. 1. A junction 243 connects the cathode of the controllableunit 230 to the conductor 222; and a load 241 and that junction connectthe cathode of the controllable unit 232 to that conductor. A junction238 and a resistor 237 connect the junction 234 to the intermediateterminal of the controllable unit 232; and the junction 238, a normallyopen, single pole, single throw switch 240, and a load 239 can connectthe junction 234 to the intermediate terminal of the controllable unit230. The load 241 should be the type of load which has a relatively highrated voltage and which is inoperable when the voltage applied theretois substantially below that rated voltage; and the voltage-droppingresistor 224 should be a resistor which can have a voltage drop that canbe added to the rated voltage of the load 241 to approximate the voltagesupplied by the source of alternating current. The voltage-droppingresistor 224 must be a resistor that can safely withstand a substantialvoltage overload. The load 239 should be a load that requires less thanone volt to make it operable, and that can withstand much highervoltages. Also, the impedance value of the load 239 should be close tothat of the resistor 237.

- When the switch 240 is open, the controllable unit 230 will benon-conductive, and hence the load 239 will be inoperable. However, thecontrollable unit 232 will be conductive-that controllable unit having alow impedance between the anode and the intermediate terminal thereof.Current will, whenever the conductor 220 is positive relative to theconductor 222, fiow from conductor 220 via resistor 224, junctions 228and 234, controllable unit 232, load 241, and junction 243 to theconductor 222. Conversely, current will, whenever the conductor 222 ispositive relative to the conductor 220, flow from conductor 222 viajunction 243, load 241, controllable unit 232, junctions 234 and 228,and resistor 224 to the conductor 220. As a result, substantially fullvoltage and substantially full power will be applied to theseries-connected resistor 224 and load 241. The voltage across that loadwill be close to the rated voltage of that load; and hence that loadwill operate. At this time, the load 241 will be operating, but the load239 will be inoperable.

When the switch 240 is closed, the voltage across the load 239 willrender that load operable; and the voltage across the lower p-n junctionof the controllable unit 230' will render that junction, and hence theoverall controllable unit 230, conductive. The impedance of thecontrollable unit 230 will be quite small after that unit has beenrendered conductive, and hence substantially all of the voltage from thesource of alternating current will appear across the voltage-droppingresistor 224. The controllable unit 230 is connected in parallel withthe series-connected controllable unit 232 and load 241; and the fewvolts developed across the controllable unit 230, and also across theseries-connected controllable unit 232 and load 241, will be too smallto permit the load 241 to be operated. Consequently, at this time theload 241 will be inoperable. The load 239 will be connected in parallelwith the upper two junctions of the controllable unit 230, and thecombined impedances of those two junctions will be quite low when thatcontrollable unit is conductive. However, because the load 239 is a loadthat requires less than a volt to make it operable, that load willcontinue to operate as long as the switch 240 is closed.

When the switch 240 is re-opened, the load 239 will become inoperable,and the load 241 will again become operable. This means that the closingand re-opening of the switch 240 will cause the control device of FIG.33 to act as a flip-flop circuit.

If desired, a resistor could be connected between the junction 228 andthe anode of the controllable unit 230. The voltage drop which wouldappear across such a resistor when the controllable unit 230 becameconductive, should not be great enough to render the load 241 operable;but should be great enough to enable the load 239 to require more than avolt to operate it. The use of such a resistor would increase the numberand types of loads that could be used as the load 239.

Referring to FIG. 34, the numerals 220 and 222 denote conductors whichcan be connected to a suitable source of alternating current. A junction228 connects the upper terminals of loads 225 and 226 to the conductor220, and junctions 242 and 236 connect the lower terminals of thoseloads to the anodes of controllable units 230 and 232. The cathodes ofthose controllable units are connected to the conductor 222 by ajunction 234. A normally-open switch 244 is connected between theintermediate terminal and the anode of the controllable unit 230 by thejunction 242; and a normally-closed switch 246 is connected between theintermediate terminal and the anode of the controllable unit 232 by thejunction 236. The switches 244 and 246 are ganged so that the switch 244will be open whenever the switch 246 is closed and so the switch 246will be open whenever the switch 244 is closed.

Whenever the switch 246 is closed, the controlable unit 232 will beconductive, and the load 226 will have substantially full power appliedto it. The controllable unit 230 will be non-conductive at such time,because the switch 244 will be open. As a result, substantially nocurrent will flow through the load 225. However, when the switch 244 isclosed and the switch 246 is opened, the controllable unit 230 willbecome conductive and the controllable unit 232 will becomenon-conductive. There- 15 upon, the load 225 will have substantiallyfull voltage and substantially full power applied to it, and the load226 wil have substantially no current flowing through it. The circuit ofFIG. 34 thus selectively applies voltage and power to the load 22-6 orto the load 225; and hence that circuit is usable as a flip-flopcircuit. The control circuit of FIG. 34 is, in some respects moredesirable than the control circuit of FIG. 33; because it has fewercomponents, because the loads 225 and 226 can have substantially fullvoltage applied to them, and because both of those loads can requirevoltages, close to their rated voltages, to make them operative.

FIG. 35 shows a flip-flop circuit which is very similar to the flip-flopcircuit shown in FIG. 34, but the circuit of FIG. 35 is usable withdirect current. When the switch 246 of FIG. 35 is a closed, current willflow from the positive conductor 220 via junction 228, load 226,junction 236, controllable unit 232, and junction 234 to the negativeconductor 222; and current will momentarily flow from conductor 220 viajunction 228, load 225, junctions 242 and 248, capacitor 252, junctions250 and 236, controllable unit 232, and junction 234 to the conductor222. The latter flow of current will charge the capacitor 252 with theleft-hand terminal thereof positive and with the right-hand terminalthereof negative. The flow of current through the load 226 and thecontrollable unit 232 will make that load operative.

The controllable unit 232 will continue to cause current to flow throughthe load 226 until the switch 244 is closed and the switch 246 isopened. When the switch 246 is opened and the switch 244 is closed, thecontrollable unit 230 will become conductive; and, thereupon, thecapacitor 252 will tend to force current to flow from the lefthandterminal thereof via junctions 248 and 242, controllable unit 230,junction 234, controllable unit 232, and junctions 236 and 250 to theright-hand terminal of that capacitor. At such time, the controllableunit 232 will become non-conductive. Current will then flow fromconductor 220 via junction 228, load 225, junction 242, controllableunit 230, and junction 234 to the conductor 222; and current willmomentarily flow from conductor 220 via junction 228, load 226,junctions 236 and 250, capacitor 252, junctions 248 and 242,controllable unit 230, and junction 234 to the conductor 222. The latterflow of current will discharge the capacitor 252 and then charge thatcapacitor with the right-hand terminal thereof positive and with theleft-hand terminal thereof negative.

The controllable unit 230 will continue to conduct current, and applysubstantially full voltage and substantially full power to the load 225,until the switch 224 is reopened and the switch 246 is re-closed. Thereclosing of the switch 246 will render the controllable unit 232conductive; and, thereupon, current will tend to flow from theright-hand terminal of the capacitor 252 via junctions 250 and 236,controllable unit 232, junction 234, controllable unit 230, and thejunctions 242, 248 to the lefthand terminal of that capacitor.Thereupon, the controllable unit 230 will become non-conductive.

The circuit of FIG. 35 can be used as a flip-flop circuit which isoperable on direct current. That circuit will normally apply voltage andpower to the load 226, but will immediately respond to shifting of theswitches 244 and 246 to halt any further application of voltage andpower to that load and to appl voltage and power to the load 225. Whenthe switches 244 and 246 are subsequently restored to their normalpositions, the circuit of FIG. 35 will halt any further application ofvoltage and power to the load 225 and will apply voltage and power tothe load 226.

Referring to FIG. 36, the numerals 260 and 262 denote conductors whichcan be connected to a suitable source of alternating current. A junction268 connects the conductor 260 to one terminal of an A.C. motor 269 andto one terminal of a lamp 270. A junction 266 and a junction 272 connectthe other terminal of that motor and the other terminal of that lamp tothe anode of a controllable unit 276 and to the cathode of acontrollable unit 278. A junction 274 connects the cathode of thecontrollable unit 276 and the anode of the controllable unit 278 to theconductor 262, and thus to the other side of the source of alternatingcurrent. An adjustable resistor 280 and a photo-resistive cell 282 areconnected in series between the intermediate terminals of thecontrollable units 276 and 278. The light from the lamp 270 is directedtoward the photo-resistive cell 282 and the intensity of that light willcontrol the ohmic value of that photo-resistive cell. The adjustableresistor 280 will be set so that sum of its ohmic value and of the ohmicvalue of the photo-resistive cell 282 will, throughout the anticipatedrange of luminosity of the lamp 270, render the controllable units 276and 278 conductive.

When the conductor 260 is positive relative to the conductor 262,current will flow via junction 268, the parallel-connected motor 269 andlamp 270, junctions 266 and 272, controllable unit 276, and junction 274to the conductor 262; and that flow of current will cause the rotor ofthat motor to rotate and will illuminate the lamp 270. When theconductor 262 is positive relative to the conductor 260, current willflow via junction 274, the controllable unit 278, junctions 272 and 266,the parallelconnected motor 269 and lamp 270, and junction 268 to theconductor 260; and that flow of current will keep the rotor of the motor269 rotating and will keep the lamp 270 illuminated.

The rotor of the motor 269 will rotate at a speed which is controlled bythe setting of the adjustable resistor 280 and by the load on thatmotor. If that load increases and tends to slow down the rotor of thatmotor, the back E.M.F. of that motor will tend to decrease, with aconsequent increase in the voltage across that motor. That increase involtage will cause the lamp 270 to become brighter; and the resultingincrease in light reaching the photo-resistive cell 282 will reduce theresistance of that cell. Thereupon, the controllable units 276 and 278will conduct throughout longer portions of the half cycles of thealternating current, and will thereby increase the power and voltagesupplied to the motor 269. That increased power and voltage will causethe rotor of the motor to return to its normal speed; and, as that rotorreturns to that speed, the of that motor will decrease and the voltageacross the motor 269 and across the lamp 270 will decrease to its normallevel. Thereupon, the resistance of the photo-resistive cell 282 willincrease to its normal level; and the controllable units 276 and 278will again conduct current throughout the desired portions of the halfcycles of the alternating current.

If the load on the motor 269 of FIG. 36 were to decrease, the rotor ofthat motor would tend to speed up; and the consequent increase in backwould decrease the voltage across that motor. The consequent decrease involtage across the lamp 270 would reduce the luminosity of that lamp;and the resulting decrease in light falling on the photo-resistive cell282 would cause the resistance of that cell to increase. That increasedresistance would shorten the lengths of time during which thecontrollable units 276 and 278 were conductive during the half cycles ofthe alternating current; and the resulting reduction in the powersupplied to the motor 269 would cause the rotor of that motor to slowdown to the desired speed. As that rotor slowed down, the voltage acrossthe motor 269 would increase to the desired value, and the luminosity ofthe lamp 270 would increase to the desired level. Thereupon, theresistance of the photo-resistive cell 282 would decrease to the desiredlevel; and the controllable units 276 and 278 would again conductcurrent throughout the desired portions of the half cycles of thealternating current.

It should be noted that the control circuit shown by FIG. 36 provides adesirable compounding action. Specifically, as the lamp 270 brightenswith increases in the load on the motor 269, and as the photo-resistivecell 282 causes the controllable units 276 and 278 to increase thevoltage applied to the motor 269, the lamp 270 will experience a furtherbrightening. That further brightening will additionally decrease theohmic value of the photoresistive cell 282, and will thereby cause thecontrollable units 276 and 278 to provide a further increase in thevoltage applied to the motor 269. Conversely, as the load on the motor269 lightens and the luminosity of the lamp 270 decreases, the increasedohmic resistance of the photo-resistive cell 282 will cause thecontrollable units 276 and 278 to decrease the voltage supplied to themotor 269. The lamp 270 will respond to that decreased voltage to becomestill less bright; and, thereupon, the ohmic value of thephoto-resistive cell 282 will increase still further and will cause thecontrollable units 276 and 278 to additionally decrease the voltagesupplied to the motor 269. This compounding action is desirable becauseit enables the control circuit of FIG. 36 to provide exceedingly promptcorrections in the values of the voltage which the controllable units276 and 278 apply to the motor 269. Consequently, the control circuit ofFIG. 36 is able to hold the voltage across the motor 269 substantiallyconstant despite changes in the load applied to that motor; and thismeans that the motor 269 will operate substantially in the manner of aconstant torque, variable speed motor. By proper adjustment of the ohmicvalue of the adjustable resistor 280, the speed of the motor 269 can bevaried over a wide range; but once the adjustable resistor 280 has beenset to provide a desired speed for the motor 269, the control circuit ofFIG. 36 will automatically maintain that speed.

Referring to FIG. 37, the numerals 286 and 288 denote conductors whichare connected to a suitable source of alternating current. Junctions 290and 302 connect a load 298 and a controllable unit 300 in series acrossthat source of alternating current. A controllable unit 304 has thecathode thereof connected to the intermediate terminal of thecontrollable unit 300, and has the anode thereof connected to the anodeof the controllable unit 300 by junctions 294, 292 and 290 and by load298. The controllable unit 304 constitutes the control circuit for thecontrollable unit 300. The controllable units 300 and 304 can beidentical to the controllable unit 50 of FIG. 1.

A heater 306 is connected between the junctions 292 and 302, and thus isconnected across the source of alternating current. That heater isdisposed adjacent the controllable unit 304, and it will maintain thetemperature of that controllable unit above ambient temperatures. Afixed resistor 308 is connected between the intermediate terminal andthe anode of the controllable unit 304 by unctions 310, 296 and 294; anda series-connected resistor 312 and a single pole, single throw switch314 are connected in parallel with the resistor 308 by the unctions 310and 296. The ohmic value of the resistor 308 Is great enough to keep thecontrollable unit 304 non-conductive whenever the switch 314 is open andthat controllable unit is at the temperature level which is normallyestablished by the heat from the heater 306. The ohmic value of theresistor 312 is quite small, and hence the controllable unit 304 willbecome highly conductive whenever the switch 314 is closed. As a matterof fact, the ohmic value of the resistor 312 is so small that wheneverthe switch 314 is closed the controllable unit 304 will be heated to atemperature above the temperature that is normally established for thatcontrollable unit by the heater 306.

When the switch 314 is open, the controllable unit 304 will benon-conductive, and will thus constitute a large impedance in thecontrol circuit of the controllable unit 300. The latter controllableunit will respond to that large impedance to remain non-conductive.However, when the switch 314 is closed, the controllable unit 304 willbecome conductive and will cause the controllable 18 unit 300 to becomeconductive. The value of the cur rent flowing through the controllableunit 304 will be high, while the switch 314 is closed; and hence thetermperature of that controllable unit will rise above the" temperaturewhich the heater 306 normaslly establishes for that controllable unit.When the switch: 314' is reopened, the controllable unit 304 will,because of its higher-than-normal temperature, remain conductive for ashort period of time, even though the ohmic value of the resistor 308 isgreat enough to keep that controllable unit non-conductive when thetemperature of that controllable unit is at the level which is normallyestablished by the heater 306. The controllable unit 304 will remainconductive, and hence the controllable unit 300 will remain conductive,until the controllable unit 304 cools down and approaches thetemperature which is normally established for that controllable unit bythe heater 306. As the temperature of the controllable unit 304approaches that temperature level, .the controllable unit 304 will againbecome non-conductive, and the controllable unit 300 also will againbecome non-conductive.

The closing and subsequent re-opening of the switch 314 caused thecontrollable element 300 to become conductive, and then to remainconductive for a predetermined length of time after the switch 314 wasre-opened. Consequently, the control circuit of FIG. 37 can be used as atime-delay circuit. The amount of time delay provided between there-opening of the'switch 314 and the rendering of the controllable unit300 non-conductive can be adjusted by appropriate selection of the valueof the resistor 312 and by appropriate selection of the temperaturewhich is normally established for the controllable unit 304 by theheater 306.

Referring to FIG. 38, the numerals 316 and 318 denote conductors whichcan be connected to a suitable source of alternating current. Junctions322, 320 and 338 connect a load 334 and a controllable unit 336 acrossthose conductors. A controllable unit 340' is connected between theintermediate terminal of the controllable unit 336 and the junction 320by a junction 324; and the former controllable unit constitutes thecontrol circuit for the latter controllable unit. A heater 342 isconnected between the junctions 322 and 338 by a junction 337; and thatheater is positioned close to the controllable unit 340 to maintain thetemperature of that controllable unit above the ambient temperatures. Aresistor 344 is connected between the intermediate terminal of thecontrollable unit 340- and the junction 324 by a junction 326. A load328 and a controllable unit 332 are connected in series between thejunctions 326 and 337 by a junction 330. The controllable units 336, 340and 332 can be identical to the controllable unit 50 of FIG. 1. A singlepole, single throw switch 348 is connected between the junction 330 andthe intermediate terminal of the controllable unit 3325 and a singlepole, single throw switch 346 is connected between the junc tion 330 andthe intermediate terminal of the controllable unit 340. The switches 346and 348 are ganged so the switch 346 will be closed whenever the switch348 is open, and so the switch 346 will be open whenever the switch 348is closed. Normally the switch 346 is closed and the switch 348 is open.

Whenever the switch 348 is open, the controllable unit 332 will benon-conductive; because the impedance of the control circuit for thatcontrollable unit will be virtually infinite. Whenever the switch 346 isopen, the controllable unit 340 will be non-conductive, because theresistor 344 will have such a large ohmic value that the controllableelement 340 will be unable to become conductive. As long as thecontrollable unit 340 is non-conductive, the controllable unit 336 alsowill be non-conductive; because the former controllable unit willconstitute a control circuit with an impedance that is too great topermit the latter controllable unit to be- 19 come conductive. However,whenever the controllable unit 340 becomes conductive, the controllableunit 336 will become conductive.

Because the switch 346 is normally closed and the switch 348 is normallyopen, the controllable units 340 and 336 will normally be conductive andthe controllable unit 332 will normally be non-conductive. Thecontrollable unit 340 will be heated by heat from the heater 342 andwill also be heated by the current flowing through it. As a result, thetemperature of that controllable unit will be higher than ambienttemperatures.

Whenever it is desirable to render the controllable unit 332 conductiveand to render the controllable units 340 and 336 non-conductive, theswitches 346 and 348 will be shifted-the switch 346 being shifted toopen position and the switch 348 being shifted to closed position.Because the controllable unit 340 is in a heated condition, due to theheat received from the heater 342 and also due to the heat generated bythe current flowing through it, that controllable unit will not becomenon-conductive immediately-even though the ohmic value of the resistor3-44 is large enough to keep that controllable unit from becomingconductive whenever that controllable unit is at ambient temperature.Not until the temperature of the controllable unit 340 decreasessufficiently to approach the ambient temperatures will that controllableunit become non-conductive. As long as the controllable unit 340 remainsconductive, the controllable unit 336 also will remain conductive; andthe latter controllable unit will effectively short the series-connectedcontrollable unit 332 and load 328. Consequently, even when the switch346 has been opened and the switch 348 has been closed, the controllableunit 332 will not become conductive until after the temperature of thecontrollable unit 340 has decreased sufficiently to approach the ambienttemperature. Once the temperature of the controllable unit 340 hasapproached the ambient temperature, that controllable unit and thecontrollable unit 336 will become non-conductive, and then thecontrollable unit 332 will immediately become conductive and will causecurrent to flow through the load 328. The controllable units 340 and 336will then remain non-conductive, and the controllable unit 332 willremain conductive, as long as the switch 348 is closed and the switchv346 is open. When the switch 348 is reopened and the switch 346 isre-closed, the controllable unit 332 will immediately becomenon-conductive and the controllable units 340 and 336 will immediatelybecome conductive.

In keeping the controllable unit 332 from becoming conductive as soon asthe switches 346 and 348 are shifted from the positions shown by FIG.38, and in permitting the controllable unit 332 to become conductiveonly after the controllable unit 340 has cooled, the control circuit ofFIG. 38 constitutes a delay-to-make control circuit for the load 328.The amount of time delay between the opening of switch 346 and theclosing of switch 348 and the rendering of the controllable unit 332conductive can be adjusted by changing the ohmic value of the resistor344 and by adjusting the amount of heat which the heater 342 supplies tothe controllable unit 340.

The control circuit shown in FIG. 39 is substantially identical to thecontrol circuit shown in FIG. 38the only diiferences between the twocircuits being that the switch 346 in FIG. 39 is normally open whereasthe similarly-numbered switch in FIG. 38 is normally closed, and theswitch 348 in FIG. 39 is normally closed whereas the similarly-numberedswitch in FIG. 38 is normally open. The controllable unit 340 in FIG. 39is normally non-conductive, because the resistor 344 has such a highimpedance value that the lower p-n junction of that controllable unit340 is normally non-conductive. Because the controllable unit 340 isnormally non-conductive, the controllable unit 336 also is normallynon-conductive. The controllable unit 332 will, however, normally be 2Oconductive because the switch 348 is normally closed.

When the switch 346 is closed and the switch 348' is opened, thecontrollable unit 332 will become non-conductive and the controllableunit 340 will become conductive. Thereupon, the controllable unit 336also will become conductive. The consequent flow of current through thecontrollable unit 340 will heat that controllable unit; and, becausethat controllable unit also is heated by the heater 342, the temperatureof that controllable unit will be considerably above the ambienttemperature. As a result, when the switch 346 is re-opened, thecontrollable unit 340 will continue to conduct current; and hence thecontrollable unit 336 also will continue to conduct current. Thosecontrollable units will continue to conduct current until thetemperature of the controllable unit 340 decreases sufliciently toapproach the ambient temperature. As a result, the control circuit ofFIG. 39 can be used as a slow-to-break circuit for the load 334.

Referring to FIG. 40, the numerals 350 and 352 denote conductors whichcan be connected to a suitable source of alternating current. A load 354has one terminal thereof connected to the conductor 350', and the otherterminal of that load is connected to the anode of a controllable unit358 by a junction 356. The cathode of that controllable unit isconnected to the conductor 352. The controllable unit 358 can beidentical to the controllable unit of FIG. 1.

A terminal 362 is connected to the anode of the controllable unit 358 bya junction 356, and a terminal 364 is connected to the intermediateterminal of that controllable unit. The terminals 362 and 364 can beconnected to any desired signal source which can constitute part of abi-directional path between the junction 356 and the intermediateterminal of the controllable unit 358. For example, the resistor of anR-C coupling network could be connected between the terminals 362 and364. Also, if desired, the secondary winding of a transformer, or onecapacitor of a split-fed capacitor network, could be connected betweenthe terminals 362 and 364. Additionally, if desired, the output of aflip-flop circuit, a counter, or the like could be connected to theterminals 362 and 364. Further, if desired, a storage battery could beselectively connected to or disconnected from the terminals 362 and 364to cause the controllable unit 358 to vary the voltage and powersupplied to the load 354. In fact, many diflerent kinds of pulse-formingor pulseshaping circuits could be connected between the terminals 362and 364. Where, as in the case of a photo-voltaic cell or a storagebattery, the signal source alternately aids and bucks the voltagedeveloped across the lower p-n junction of the controllable unit 358,the voltage waveform applied to the load 354 will not be a truesinusoid, but will have positive-going and negative-going portions ofunequal amplitude. If desired, a fixed or adjustable impedance could beconnected between the junction 356 and the terminal 362 or between theterminal 364 and the intermediate terminal of the controllable unit 358.The value of that impedance would be selected to enable the sub-circuitconnected between the terminals 362 and 364 to provide the desiredconducting characteristics for the controllable unit 358.

If desired, the signal-injection which is used in the control circuit ofFIG. 40 could be used with the flip-flop circuit shown by FIG. 33.Specifically, the switch 240 of FIG. 33 could be replaced by asignal-injection sub-circuit which normally had an impedance greatenough to keep the controllable unit 230 from being rendered conductive,but which could respond to the injection of a signal to make thatcontrollable unit conductive. Where such a sub-circuit was used toreplace the switch 240, the flip-flop circuit of FIG. 33 could beactuated without any need of moving parts such as switches.

Referring to FIG. 41, the numerals 370 and 372 denote conductors whichcan be connected to a suitable source of alternating current. Theconductor 370 is connected to one terminal of a load 374, and the otherterminal of that load is connected to the anode of a controllable unit378 by a junction 376. The cathode of that controllable unit isconnected to the conductor 372 by a junction 380. That controllable unitcan be identical to the controllable unit 50 in FIG. 1.

The numeral 383 denotes an adjustable resistance bridge which has anadjustable resistor 384 as one leg thereof; and one of the inputterminals of that resistance bridge is connected to the junction 376 bya junction 382, and the other input terminal of that resistance bridge,isconnected to the junction 380. One of the output terminals of thatresistance bridge is connected to the intermediate terminal of thecontrollable unit 378, and the other output terminal of that resistancebridge is connected to the junction 382 by an adjustable resistor 386.The ohmic values of the adjustable resistor 384 and of the otherresistors of the resistance bridge 383, and the ohmic value of theadjustable resistor 386 are selected to enable the controllable unit 378to be rendered conductive. Adjustment of the setting of the adjustableresistor 384 will adjust the voltage drop across the output terminals ofthe resistance bridge 383; and adjustment of the setting of theadjustable resistor 386 will control the voltage drop across theseries-connected load 374, adjustatble resistor 386, adjustableresistance bridge 383, and the lower p-n junction of the controllableunit 378. Consequently, appropriate adjustments of the adjustableresistors 384 and 386 will determine the value of the voltage and powersupplied to the load 374.

If desired, the adjustable resistance bridge 383 could be supplanted byan adjustable inductance bridge or an adjustable capacitance bridge.Further, if desired, the legs of the bridge 383 could have any desiredcombination of resistance and inductance therein. Moreover, wheredesired, different kinds of resistances, capacitances, and inductancescould be used in forming that bridge. Thus, one or more of thecomponents of the bridge 383 could be a thermistor, a temperaturesensitive paint or coating, a tapped impedance associated with athermostat or contact-equipped thermometer, a photo-resistive cell, apressure-sensitive paint or coating, a pressurestat associated with atapped impedance, a humidistat associated with a tapped impedance, orthe like. The bridge 383 of FIG. 41 is a true bridge whereas the bridgesof FIGS. 9-11 are essentially resistors, capacitors and inductors,respectively, that are connected in series-parallel relation. Wheredesired, the bridge 383 or the bridges of FIGS. 9-11 could be arrangedso each of the legs thereof was a series-parallel combination ofresistors, inductors and capacitors.

Referring to F lG. 42, the numerals 388 and 390 denote conductors whichcan be connected to a suitable source of alternating current. A load 392has one terminal thereof connected to the conductor 388, and has theother terminal thereof connected to the anode of a controllable unit 400by a junction 394. The cathode of that controllable unit is connected tothe conductor 390. That controllable unit can be identical to thecontrollable unit 50 of FIG. 1.

A sensing element 402, which can have the form of a relatively largemetal plate, is connected to the intermediate terminal of thecontrollable unit 400; and a similar sensing element 398 is connected tothe junction 394 by an adjustable resistor 396. The sensing elements 398and 402 are spaced apart; and they can be used to sense the presence ofan object or can require an object to bridge them. If desired, thatobject can be a human body; and, where the sensing elements 398 and 402are large enough and are set close enough together, the movement of aperson into close proximity to those sensing elements will render thecontrollable unit 400 conductive. Where it is desirable that a personactually touch the sensing elements 398 and 402 to render thecontrollable unit 400 conductive, those sensing elements can be madesmaller in size and can be spaced further apart; and the operator willthen have to touch those sensing elements to establish the required lowresistance between the junction 394 and the intermediate terminal of theCOrrtrollable unit 400. Adjustment of the setting of the adjustableresistor 396 will determine the sensitivity of the control circuit ofFIG. 42.

Referring to FIG. 43, the numerals 404 and 406 denote conductors whichcan be connected to a suitable source of alternating current. A junction408 connects the conductor 404 to one terminal of a load 410, and ajunction 412 connects the other terminal of that load to the anode of acontrollable unit 414. The cathode of that controllable unit isconnected to the conductor 406 by a junction 416. A thermistor 418 andan adjustable resistor 420 are connected in series between the junction412 and the intermediate terminal of the controllable unit 414. Thatcontrollable unit can be identical to the controllable unit 50 ofFIG. 1. A heating element 422 is connected between the junctions 408 and416. The sum of the minimum ohmic values of the thermistor 418 and ofthe adjustable resistor 420 should be small enough to render thecontrollable unit 414 conductive.

Where the thermistor 418 is the type of thermistor which experiences adecrease in ohmic value as the temperature thereof. increases, thecontrol circuit of FIG. 43 will constitute a slow-to-make circuit.Specifically, the room temperature ohmic value of the thermistor 418will add to the ohmic value of the adjustable resistor 420 to make thetotal ohmic value between the junction 412 and the intermediate terminalof the controllable unit 414 too great to permit that controllable unitto become conductive. However, when the conductors 404 and 406 aresuitably connected to the source of alternating current, current willflow from conductor 404 via junction 408, heating element 422 andjunction 416 to the conductor 406; and that current will heat thatheating element. That heating element will be disposed inheat-transferring relation to the thermistor 418; and that thermistorwill respond to heat from that heating element to experience a decreasein the ohmic value thereof. When that ohmic value falls to apredetermined level, the controllable unit 414 will become conductive.By selecting the proper rating for the heating element 422, by providingthe proper spacing between that heating element and the thermistor 418,or by adjusting the value of the adjustable resistor 420, the desiredtime delay between the connecting of the conductors 404 and 406 to thesource of alternating current and the rendering of the controllable unit414 conductive can be obtained.

The control circuit of FIG. 43 can be used as a circuitinterruptingdevice, where the thermistor 418 is the type of thermistor whichexperiences an increase in ohmic value as the temperature thereofincreases. With such a thermistor, the adjustable resistor 420 will beset so the total ohmic value between the junction 412 and theintermediate terminal of the controllable unit 414, at the temperaturewhich is normally established by the heating element 422, will be lowenough to render the controllable unit 414 conductive. This means thatwhen the conductors 404 and 406 are connected to the source ofalternating current, and when the voltage across the controllable unit414 is close to its intended value, the heat from the heating element422 will maintain the temperature, and hence the ohmic value of thethermistor 418, at a level which will permit the controllable unit 414to be conductive. However, in the event the voltage applied to theconductors 404 and 406 were to increase to an undesired value, the heatgenerated by the heating element 422 would increase and the thermistor418 would respond to the increased heat from that heating element toincrease the ohmic value thereof. Prior to the time the increasedvoltage applied to the conductors could injure the load 410 or thecontrollable unit 414, the heat from 23 the heating element 422 wouldhave caused the thermistor 418 to increase its ohmic value to the pointthat the controllable unit 414 would become non-conductive.

It will be noted that the heating element 422 is connected between thejunctions 408 and 416; and hence the voltage across that heating elementis substantially independent of the conductivity of the controllableunit 414. This is desirable, because it will permit that heating elementto continue to generate heat during those periods when the controllableunit 414 is rendered non-conductive. As a result, the heating element422 will continue to keep the thermistor 418 heated, and will thus keepthe controllable unit 414 non-conductive, as long as the unduly highvoltage continues.

If desired, a thermostat could be substituted for the thermistor 418 ofFIG. 43. Also, if desired, a temperaturesensitive paint or coating couldbe substituted for that thermistor.

FIGS. 14 A--C through 22 A-C show some of the voltage waveforms whichcan be obtained from the controllable unit 50 of FIG 1. To obtain agiven voltage waveform, it is only necessary to adjust the value of theadjustable resistor 68, or other impedance, connected between theterminals 58 and 60, As the value of that impedance is adjusted, thevoltage across the load, the voltage across the controllable unit 50,and the voltage across the lower p-n junction of that controllable unitwill vary. For example, when the adjustable resistor 68 was set to havea value of one megohm, the voltage across the load was approximatelyfifty eight volts, the voltage across the anode-cathode circuit of thecontrollable unit 50 was approximately ninety two volts, and the voltageacross the lower p-n junction of that controllable unit wasapproximately seven tenths of a volt. When the ohmic value of thatadjustable resistor was reduced to three hundred and thirty thousandohms, the voltage across the load increased less than a volt, thevoltage across the controllable unit 50 dropped to approximately seventyone volts, and the voltage across the the lower p-n junction of thatcontrollable unit increased to about one and four tenths volts. When theohmic value of the adjustable resistor 68 was reduced to one thousandohms, the voltage across the load increased to approximately seventyvolts, the voltage across the controllable unit 50 decreased to aboutforty eight volts, and the voltage across the lower p-n junction of thatcontrollable unit increased to about three and six tenths volts. Whenthe ohmic value of the adjustable resistor 68 was reduced to one hundredohms, the voltage across the load increased to about ninety four volts,the voltage across the controllable unit 50 decreased to about twentytwo volts, and the voltage across the lower p-n junction of thatcontrollable unit increased to about five and eight tenths volts. Whenthe ohmic value of the adjustable resistor 68 was reduced to ten ohms,the value of the voltage across the load increased to one hundred andeight volts, the voltage across the controllable unit 50 decreased toabout eight volts, and the voltage across the lower p-n junction of thatcontrollable unit increased to about six and one half volts. Thesevarious various voltages were measured when the line voltage wasapproximately one hundred and eighteen volts root means square. As aresult, it should be apparent that proper selection of the value of theimpedance connected to the intermediate terminal of the controllableunit 50 will permit a desirable range of voltages to be developed acrossthe load 67, across the controllable unit 50, or across the lower p-njunction of that controllable unit.

In the various control circuits provided by the present invention, theloads can be wholly resistive in nature, can be wholly inductive innature, can be wholly capacitive in nature, can be both resistive andinductive in nature, can be both resistive and capacitive in nature, canbe both inductive and capacitive in nature, or can be resistive andinductive and capacitive in nature. Further, those loads can bepower-consumng devices, can be control devices, or can be the controlcircuits of further controllable units. As a result, the controlcircuits provided by the present invention have widespread applicationand use.

Whereas the drawing and accompanying description have shown anddescribed several preferred embodiments of the present invention itshould be apparent to those skilled in the art that various changes maybe made in the form of the invention without affecting the scopethereof.

What I claim is:

1. A control device that comprises:

(a) a controllable unit which has a p-n junction, an

n-p junction, a second p-n junction, and an intermediate terminalbetween said n-p junction and said second p-n junction,

(b) the p-type layer of the first said p-n junction being connectable toone side of a source of bi-directional current to constitute the anodeof said controllable unit,

(0) the n-type layer of said second p-n junction being connectable tothe other side of said source of bidirectional current to constitute thecathode of said controllable unit,

(d) a control circuit connectable between said one side of said sourceof bi-directional current and said intermediate terminal to constitute abi-directional path for current, and

(e) a load connectable in series with said controllable unit across saidsource of bi-directional current,

(f) said control circuit permitting bi-directional current to flowthrough it and having an impedance value low enough to enable all ofsaid junctions of said controllable unit to permit current fiowtherethrough in both directions which is greater than the level ofreverse leakage current flow and thereby enable said controllable unitto supply more than half-wave power and half-wave voltage to said load.

2. A control device that comprises:

(a) a controllable unit which has a p-n junction, an

n-p junction, a second p-n junction, and an intermediate terminalbetween said n-p junction and said second p-n junction,

(b) the p-type layer of the first said p-n junction being connectable toone side of a source of bi-directional current to constitute the anodeof said controllable unit,

(c) the n-type layer of said second p-n junction being connectable tothe other side of said source of hidirectional current to constitute thecathode of said controllable unit,

(d) a control circuit connectable between said one side of said sourceof bi-directional current and said intermediate terminal to constitute abi-directional path for current, and

(e) a load connectable in series with said controllable unit across saidsource of bi-directional current,

(if) said control circuit permitting bi-directional current to flowthrough it and having an impedance value low enough to enable all ofsaid junctions of said controllable unit to permit current flowtherethrough in both directions which is greater than the level ofreverse leakage current flow and thereby enable said controllable unitto supply more than half wave power and half-wave voltage to said load,

(g) said control circuit including an impedance which has an impedancevalue less than the sum of the nonconductive impedance values of thefirst said p-n junction and of said n-p junction.

3. A control device as claimed in claim 1 wherein said control circuitincludes a capacitance.

4. A control device as claimed in claim 1 wherein said control circuitincludes an inductance.

5. A control device that comprises:

(a) a controllable unit which has a p-n junction, an

n-p junction, a second p-n junction, and an intermediate terminalbetween said n-p junction and said second p-n junction.

(b) the p-type layer of the first said p-n junction being connectable toone side of a source of bi-directional current to constitute the anodeof said controllable unit,

() the n-type layer of said second p-n junction being connectable to theother side of said source of bidirectional current to constitute thecathode of said controllable unit,

((1) a control circuit connectable between said one side of said sourceof bi-directional current and said intermediate terminal to constitute abi-directional path for currrent, and

(e) a load connectable in series with said controllable unit across saidsource of bi-directional current,

(f) said control circuit permitting bi-directional current to flowthrough it and having an impedance value low enough to enable all ofsaid junctions of said controllable unit to permit current flowtherethrough in both directions which is greater than the level ofreverse leakage current flow and thereby enable said controllable unitto supply more than half-wave power and half-wave voltage to said load,

(g) the impedance value of said control circuit selectively beinggreater than or less than the sum of the non-conductive impedance valuesof the first said p-n junction and of said n-p junction,

(h) whereby said control circuit can selectively render saidcontrollable unit conductive.

6. A control device as claimed in claim 1 wherein said control circuitincludes a switch.

7. A control device as claimed in claim 1 wherein said control circuitincludes a bridge.

8. A control device as claimed in claim 1 wherein said control circuitincludes sensing elements that are spaced apart and that can respond tothe movement of an object into close proximity with them to render saidcontrollable unit conductive.

9. A control device as claimed in claim 1 wherein said control circuitincludes sensing elements that are spaced apart and that can coact withan object that bridges them to render said controllable unit conductive.

10. A control device that comprises:

(a) a controllable unit which has a p-n junction, an

n-p junction, a second p-n junction, and an intermediate terminalbetween said n-p junction and said second p-n junction,

(b) the p-type layer of the first said p-n junction being connectable toone side of a source of bi-directional current to constitute the anodeof said controllable unit,

(c) the n-type layer of said second p-n junction being connectable tothe other side of said source of hidirectional current to constitute thecathode of said controllable unit, and

(d) a control circuit connectable between said one side of said sourceof bi-directional current and said intermediate terminal to constitute abi-directional path for current, and

(e) a load connectable in series with said controllable unit across saidsource of bi-directional current,

(f) said control circuit permitting bi-directional current to fiowthrough it and having an impedance value low enough to enable all ofsaid junctions of said controllable unit to permit current flowtherethrough in both directions which is greater than the level ofreverse leakage current flow and thereby enable said controllable unitto supply more than half-wave power and half-wave voltage to said load,

(g) said second p-n junction having an area greater than the area ofsaid n-p junction.

11. A control device that comprises:

(a) a controllable unit which has a p-n junction, an

n-p junction, a second p-n junction, and an intermediate terminalbetween said n-p junction and said second p-n junction,

(b) the p-type layer of the first said p-n junction being connectable toone side of a source of bi-directional current to constitute the anodeof said controllable unit,

(c) the n-type layer of said second p-n junction being connectable tothe other side of said source of bidirectional current to constitute thecathode of said controllable unit,

(d) a control circuit connectable between said one side of said sourceof bi-directional current and said intermediate terminal to constitute abi-directional path for current, and

(e) a load connectable in series with said controllable unit across saidsource of *bi-directional current,

(f) said control circuit permitting bi-directional current to flowthrough it and having an impedance value low enough to enable all ofsaid junctions of said controllable unit to permit current flowtherethrough in both directions which is greater than the level ofreverse leakage current flow and thereby enable said controllable unitto supply more than half-Wave power and half-wave voltage to said load,

(g) said control circuit having an impedance value that causes saidcontrollable unit to apply substantially full voltage and substantiallyfull power to said load.

12. A control device that comprises:

(a) a controllable unit which has a p-n junction, an

n-p junction, 2. second p-n junction, and an intermediate terminalbetween said n-p junction and said second p-n junction,

(b) the p-type layer of the first said p-n junction being connectable toone side of a source of bi-directional current to constitute the anodeof said controllable unit;

(c) the n-type layer of said second p-n junction being connectable tothe other side of said source of hidirectional current to constitute thecathode of said controllable unit,

((1) a control circuit connectable between said one side of said sourceof bi-directional current and said intermediate terminal to constitute abi-directional path for current, and

(e) a load connectable in series with said controllable unit across saidsource of bi-directional current,

(f) said control circuit permitting bi-directional current to flowthrough it and having an impedance value low enough to enable all ofsaid junctions of said controllable unit to permit current flowtherethrough in both directions which is greater than the level ofreverse leakage current flow and thereby enable said controllable unitto supply more than half-wave power and half-wave voltage to said load,

(g) said control circuit having an impedance value that causessubstantially square wave forms to be developed across said controlcircuit.

13. A control device that comprises:

(a) a controllable unit which has a p-n junction, an

up junction, a second p-n junction, and an intermediate terminal betweensaid n-p junction and said second p-n junction,

(b) the p-type layer of the first said p-n junction being connectable toone side of a source of alternating current to constitute the anode ofsaid controllable unit,

(c) the n-type layer of said second p-n junction being connectable tothe other side of said source of alternating current to constitute thecathode of said controllable unit, and

(d) a control circuit connectable between said one 27 side of saidsource of alternating current and said intermediate terminal,

(e) said control circuit providing a bi-directional path for currentflowing through said second p-n junction and causing said controllableunit to permit bi directional current flow which is greater than thelevel of reverse leakage current flow through all of said junctionsthereof.

14. A control device that comprises:

(a) a controllable unit which has a p-n junction, an

n-p junction, a second p-n junction, and an intermediate terminalbetween said n-p junction and said second p-n junction,

(b) the p-type layer of the first said p-n junction being connectable toone side of a source of alternating current to constitute the anode ofsaid controllable unit.

(c) the n-type layer of said second p-n junction being connectable tothe other side of said source of alternating current to constitute thecathode of said controllable unit, and

(d) a control circuit connectable between said one side of said sourceof alternating current and said intermediate terminal,

(c) said control circuit providing a bi-directional path for currentflowing through said second p-n junction,

(f) said control circuit having an impedance that is small enough topermit the forward voltage drop across said second p-n junction to begreat enough to render said second p-n junction conductive and therebyrender said controllable unit conductive, and said control circuithaving an impedance that is small enough to permit the inverse voltagedrop across said second p-n junction to be great enough to render saidsecond p-n junction conductive and thereby render said controllable unitconductive with a current :flow that is greater than the level ofreverse leakage current flow.

15. A control device that comprises (a) a plurality of controllableunits,

(h) each of said controllable units having a p-n junction, an n-pjunction, a second p-n junction, and an intermediate terminal betweensaid n-p junction and said second p-n junction,

() each of said controllable units having the p-type layer of the firstsaid p-n junction thereof connectable to one lead of a plural phasealternating current source to constitute the anode of said controllableunit,

(d) each of said controllable units having the n-type layer of saidsecond p-n junction thereof connectable to a plural phase alternatingcurrent load to constitute the cathode of said controllable unit, and

(e) each of said controllable units having a control circuit connectablebetween the anode and the intermediate terminal thereof to constitute abi-directional path for current,

(f) each of said control circuits permitting bi-directional current toflow through it and having an impedance value low enough to enable allof said junctions of the controllable unit to which it is connected topermit current to flow through said controllable unit in both directionswhich is greater than the level of reverse leakage current flow andthereby enable said controllable unit to supply more than half-wavepower and half-wave voltage to said load,

(g) said controllable units being incorporated into the phases of aplural phase circuit to enable said plural phase circuit to supplyalternating current to said plural phase alternating current load.

16. A control device that comprises:

(a) a controllable unit which has a p-n junction, an

n-p junction, a second p-n junction, and an intermediate terminalbetween said n-p junction and said second p-n junction,

(b) the p-type layer of the first said p-n junction of said controllableunit being connectable to one side of a source of bi-directional currentto constitute the anode of said controllable unit,

(c) the n-type layer of said second p-n junction of said controllableunit being connectable to the other side of said source ofbi-directional current to constitute the cathode of said controllableunit,

(d) a load connected in series with said controllable unit across saidsource of bi-directional current,

(e) a control circuit for said controllable unit connected to constitutea bi-directional path for current,

(f) a second controllable unit which has a p-n junction, an n-pjunction, a second p-n junction, and an intermediate terminal betweensaid n-p junction and said second p-n junction,

(g) the p-type layer of the first said p-n junction of said secondcontrollable unit being connectable to said one side of said source ofbi-directional current to constitute the anode of said secondcontrollable unit,

(h) the n-type layer of said second p-n junction of said secondcontrollable unit being connectable to said other side of said source ofbi-directional current to constitute the cathode of said secondcontrollable unit, and

(i) a second control circuit for said second controllable unit connectedto constitute a bi-directional path for current,

(j) said control circuit permitting bi-directional current to flowthrough it and having an impedance value low enough to enable all ofsaid junctions of said second controllable unit to permit current flowtherethrough which is greater than the level of reverse leakage currentflow.

(k) said second controllable unit essentially shorting theseries-connected load and the first said controllable unit whenever saidsecond controllable unit becomes conductive,

(1) whereby said control device can be used as a flipflop circuit.

17. A control device as claimed in claim 16 wherein said second controlcircuit includes a second load.

18. A control device that comprises:

(a) a controllable unit which has a p-n junction, an

n-p junction, a second p-n junction, and an intermediate terminalbetween said n-p junction and said second p-n junction,

(b) the p-type layer of the first said p-n junction being connectable toone side of a source of bi-directional current to constitute the anodeof said controllable unit,

(0) the n-type layer of said second p-n junction being connectable tothe other side of said source of bi-directional current to constitutethe cathode of said controllable unit,

(d) a control circuit connectable between said one side of said sourceof bi-directional current and said intermediate terminal to constitute abi-directional path for current, and

(e) a load connectable in series with said controllable unit across saidsource of bi-directional current,

(f) said control circuit permitting bi-directional current to flowthrough it and having an impedance value low enough to enable all ofsaid junctions of said controllable unit to permit current flowtherethrough in both directions which is greater than the level ofreverse leakage current flow and thereby enable said controllable unitto supply more than half-wave power and half-wave voltage to said load.

